I have a 1999 s10 blazer. It acts like the cruise control is on when you take your foot off the gas. It just seems to keep going at the same speed till you hit the break. Now I have only noticed this at speeds under 40mph. The tack will read about 1200 rpm. Normally at idle it is about 600-700. I tried unplugging the cruise control and it seemed to work for a while and the problem came back about 6 weeks later.

 

Sounds like a TPS or possibly an IAC issue...any codes? Search this site-the answers are here.

 

What is the idle RPM at normal operating temperature with the transmission in park? Should be ~500 to ~600 RPM.
On the passenger side of the throttle body there are 2 small braided cables, one is for throttle, the other is for cruise. When the engine is at idle, gently push down on each cable, (much like you would check serpentine belt tension) there should not be any tension on either cable.

 

I did check the cruise control cable and it moves free. I even disconected it and it didn't help.

Not sure about the TPS or IAC. I didn't get any codes.

Any thoughts about engine temperature? Could that have an affect?

 

i would check the intake gasket if its sucking air it can idle faster and run horrible easy test is spray alittle ether on the intake itself and if it idles down ..theres your problem

 

Thanks for the thought about an air leak.

Will carb cleaner work as a spray?